1. Field of the Inventive Concept
Embodiments of the present disclosure described herein relate to a semiconductor device and a manufacturing method thereof.
2. Description of the Related Art
In general, semiconductor memory devices, including a dynamic random access memory (DRAM), may each be provided with a plurality of banks. Each of the banks may be provided with a large number of memory cells, each of them including cell transistors and cell capacitors. Defects may occur in the plurality of these memory cells for several reasons. In the case of a defect, the corresponding semiconductor memory device is treated as a defective product because it may not perform a memory function.
Meanwhile, under circumstances in which the integration density of a semiconductor memory device is gradually increased, the probability that defects will occur in a small amount of cells is typically increased. A method of treating and discarding the whole semiconductor memory device including the small amount of these defective cells as a defective product may be an inefficient treatment method of decreasing the yield of a product.
Accordingly, a method of enhancing the yield of the product by having a separate memory cell in a semiconductor memory device and replacing a defective cell with the memory cell is usually used. In other words, after a spare memory cell is made and tested in advance, when a defect occurs in a memory cell, the memory cell in which the defect occurs is repaired with the spare memory cell to address a problem in which a chip does not operate normally. Herein, the spare memory cell is referred to as a redundancy cell and a circuit which intervenes in this repair operation is referred to as a redundancy circuit.
The more redundancy cells, the more the yield of the product is increased. However, there may result in a burden to a chip size due to fuse portions which are increased according to this. Therefore, it would be useful to provide a method of minimizing the number of fuse portions and improving the yield of the product.